Vologases IV of Parthia rules the Parthian Empire from 147 to 191.

The son of Mithridates IV of Parthia (129–140), he unites the two halves of the empire which had been split between his father and Vologases III of Parthia (105–147).

He also reconquers the kingdom of Characene which seems to have been independent since the Roman invasion of the Parthian empire under Trajan (98–117).

Vologases IV may be the king Volgash of the Zoroastrian tradition, who began the gathering of the writings of Zoroaster.